This invention relates to the field of disposable containers for use in the retail packaging of products such as fast food items in the nature of sandwiches and the like, and more particularly to an arrangement for locking together the top and bottom portions of such a container in a manner which prevents inadvertant unlocking yet permits proper locking and unlocking rapidly and easily with one hand.
Prior to the present invention, a wide variety of such containers have been proposed, and many have met with a large measure of commercial success. One troublesome feature, however, connected with the design, manufacture, shipping and use of such containers is the provision of a suitable locking mechanism.
One type of locking device for such containers, the straight tongue-in-slot type, is disclosed in Jewell, U.S. Pat. No. 3,968,921 issued July 13, 1976. One problem with this type of lock is that the narrow tongue extending laterally outwardly from the edge of the container creates a troublesomely weak male locking element, although the slot locking element has the requisite strength.
Another type of locking device for such containers, the flange-in-slotted recess type, is disclosed in Haase, U.S. Pat. No. 3,876,130 issued Apr. 8, 1975. One problem with this type of lock is that the slot formed all the way across the flute or recess in the skirt creates a troublesome weak female locking element, although the elongated flange locking element has the requisite strength.
Thus, the problem heretofore unresolved by the prior art is the provision of a lock which has a male locking element stronger than a narrow outwardly directed tongue, and a female locking element stronger than that provided by a slot clear across a recess in a skirt.